Technical Field
The present invention relates to a battery system, and an electric vehicle, a movable structure, an electricity storage device, and a power supply device having the battery system.
Related Art
For a movable structure such as an electricity-driven vehicle or a power supply device storing electricity, a battery system including a battery cell which can be charged and discharged is used. Such a battery system is equipped with a device for evaluating the state of charge such as a remaining capacity of the battery cell (for example, refer to JP 2005-201743 A).
In a remaining capacity calculation device for an electricity accumulating device described in JP 2005-201743 A, a remaining capacity determined by integrating the current and a remaining capacity determined based on an estimated value of a battery open circuit voltage are weighted with weights that are constantly changed based on a current change rate, and the weighted values are combined, to determine a final remaining capacity.
The remaining capacity determined based on the integration of the current and the remaining capacity determined based on the battery open circuit voltage have respective advantages and disadvantages. However, in the remaining capacity calculation device of JP 2005-201743 A, the weights are determined based on the current change rate. Because of this, in a case where an instantaneous change of the current occurs frequently, the calculated remaining capacity would discontinuously change. Because of this, in the remaining capacity calculation device for electricity accumulating device of JP 2005-201743 A, the remaining capacity cannot be obtained with a high precision.
An advantage of the present invention is in the provision of a battery system, an electric vehicle, a movable structure, an electricity storage device, and a power supply device in which the state of charge of a battery cell can be precisely calculated.